If you like the Mavs to win the series

[freerollin]

how is this possible? i'm not questioning the math, i just don't understand how you couldn't arb this out with a positive bet on miami for the series at +157.

i have miami on a free future bet for $50 to win $425 and i have been reluctant to hedge because well its free and dallas odds have been steadily getting worse. is this right? it wouldnt be the last time i have flubbed what looked to be good on paper?